What do to with your life?

Lately, I have been feeling so desperate and lost, I don´t have a problems admitting it here, even when everybody can see and comment about this.
I felt surprised about how many times I heard the same question in my mind "What can I do with my life when I don't have any idea of what I am doing?" - How do I know if I'm not going to regret "this decisions" later.
Unfortunately, I had to learn how to do or deal with many things on my own, because, I think...at least in my case, when you're young, you usually receive your parents help and they show you the best way (Usually, they do... or they supposed to do it) But, my mother, who was my role model, passed away when I was 16 and I had already lost her some years before that as a result of a colon cancer as well as all the related problems and treatments related.
I saw how my older sisters received that help from my mother, when they had doubts about their high school, their college, their boyfriends, their prom, their first job interview, any way, all the situations you have to face when you're growing up.
Since her death, I just do how I'm supposed to! I'm always feeling that I have no choice and I mustn't mess it up trying things I'm attracted to. I can only can decide for the right way to go and nothing else.
I received a limited pension which allows me to pay for my studies, that benefit will end the next year and this October I need to choose again what carrier, technical career or course to study during that time.
I don't know what to do or think, as I said, I feel lost and desperate. I already asked for help and advice but sometimes, just saying: "I'm here for you", it doesn't change anything.

Hola Stephane, conocí el sentimiento. Espero que halles alguna dirección.